Added agent and notebook for dqn version 2.7

Added notebook and agent files for dqnv2.6

Added checkpoint agents to each dqn version. Added the notebook for dqn 2.5

Added the a2c notebook and the latest dqn run notebook

Added PPO trial run

Added run2v3 to notebooks. Updated run_2 model and best model. Added run2v3 TensorBoard and eval files to agents.

Updated run2v2 notebook

Updated run_2 agent and best model. Added evaluations and Tensorboard files to run_2.

Added final notebook files for first runs. Added Agents and evals from first runs.

Added dqn_pacmanv5_run2.ipynb

Fixed video callback freq in dqn_pacmanv5_run1.ipynb prior to training.

Updated dqn_pacmanv5_run1.ipynb to final version prior to training.

Added notebook structure for training first agent.